docs: def messageReceived(self, message):
          """
          Called on incoming message from ZeroMQ.
  
          :param message: message data
          """
          i = message.index(b'')
          assert i > 0
          (routingInfo, msgId, payload) = (
              message[:i - 1], message[i - 1], message[i + 1:])
          msgParts = payload[0:]
          self._routingInfo[msgId] = routingInfo
          self.gotMessage(msgId, *msgParts)